well, that i get, im just not sure how to do so. For example: Ba -> Ba^(2+) + _______ ??? How would i get rid of the two? is that what yhou mean im supposed to do? sorry, chemistry is very confusing to me...

well, magnesium has 12 protons - by definition,
to be a neutral atom the positive charges of the protons is canceled out by negatively charged electrons ,
(-)elections and (+)protons have a charge that is equal in magnitude and opposite in sign,
\[ _{12}\text{Mg}^0 \longrightarrow \_\_ + 2e^- \]
\[ _{12}\text{Mg}^0 -2e^- = \_\_ \]
taking away electrons from magnesium will effect the overall charge
\(0-(-2)=2\)
the nucleus of the atom will remain the same